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18-622: The entire Arctic coastal plain of Alaska with its Arctic coastal tundra has tremendous ecological importance with the densest concentration of birds in the Arctic, along with housing substantial amounts of large mammals such as whales, walrus, seals, caribou, and moose. The region includes the Arctic National Wildlife Refuge (ANWR) as well as the National Petroleum Reserve–Alaska (NPRA). Within

36-735: A 2012 U.S. Geological Survey report." Alaska North Slope (ANS) is a more expensive waterborne crude oil. Since 1987, Alaska North Slope (ANS) crude production has been in decline. As of 2020, the U.S. Geological Survey estimated 3.6 billion barrels of oil and 8.9 trillion cubic feet of natural gas in Mississippian through Paleogene strata in the central North Slope of Alaska, which are undiscovered and technically recoverable. 69°03′28″N 152°51′46″W  /  69.0578758°N 152.8628274°W  / 69.0578758; -152.8628274 Coastal plain A coastal plain (also coastal plains , coastal lowland , coastal lowlands )

54-548: A result of demand for transferring people and goods between land-based and water-based transportation at that place. Download coordinates as: The Atlantic Seaboard Fall Line , or Fall Zone , is a 1,400-kilometre (900-mile) escarpment where the Piedmont and Atlantic Coastal Plain meet in the eastern United States . Much of the Atlantic Seaboard fall line passes through areas where no evidence of faulting

72-678: A series of rapids down to the tidal estuary of the James River. Columbia, South Carolina , is similar as well with the Congaree River . Before navigation improvements such as locks, the fall line was often the head of navigation of rivers due to rapids and waterfalls, such as the Little Falls of the Potomac River . Numerous cities were founded at the intersection of rivers and the fall line. U.S. Route 1 links many of

90-708: Is an area of flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and an upland area. Some of the largest coastal plains are in Alaska and the southeastern United States . The Gulf Coastal Plain of North America extends northwards from the Gulf of Mexico along the Lower Mississippi River to the Ohio River , which is a distance of about 981 miles (1,579 km). The Atlantic Coastal Plain runs from

108-703: Is present. The fall line marks the geologic boundary of hard metamorphosed terrain—- the product of the Taconic orogeny —- and the sandy, relatively flat outwash plain of the upper continental shelf, formed of unconsolidated Cretaceous and Tertiary sediments . Examples of the Fall Zone include the Potomac River's Little Falls and the rapids in Richmond, Virginia , where the James River falls across

126-733: The Deccan Plateau , along the western and eastern coasts of India. They extend for about 6,150 km from the Rann of Kutch in the west to West Bengal in the east. They are broadly divided into the Western Coastal Plains and the Eastern Coastal Plains . The two coastal plains meet at Kanyakumari , the southernmost tip of the Indian mainland. The eastern coastal plain is located between The Bay of Bengal and

144-485: The New York Bight to Florida. Coastal plains can form in one of two ways. Some start as a continental shelf , a flat piece of land located below sea level, and are created when the ocean level falls, exposing the land. Others develop when river currents carry sediment into the ocean, which is deposited and builds up over time until it forms a coastal plain. The Coastal Plains of India lie on either side of

162-942: The Pacific Ocean . In 2005 the USGS estimated that the Arctic Alaska Petroleum Province, encompassing all the lands and adjacent Continental Shelf areas north of the Brooks Range-Herald arch (see map) held more than 50 billion bbl of oil and natural-gas liquids and 227 trillion cubic feet of gas. The source rock for the Prudhoe Bay Oil Field and neighboring reserves is also a potential source for unconventional tight oil and shale gas – possibly containing "up to 2 billion barrels of technically recoverable oil and up to 80 trillion cubic feet of natural gas, according to

180-404: The coastal plain is softer sedimentary rock . A fall line often will recede upstream as a river cuts out the uphill dense material, forming "c"-shaped waterfalls and exposing bedrock shoals . Because of these features, riverboats typically cannot travel any farther inland without portaging , unless locks are built. The rapid change of elevation of the water and resulting energy release make

198-490: The 1920s, "To keep warm and to cook with, the Eskimo was burning hunks of dark stuff he just picked up on the ground all around his tent. This was oil from seepage under the tundra. The Eskimos had always known about the oil, long before there was any drilling for it." The North Slope region includes the National Petroleum Reserve–Alaska (NPRA), which was established by President Warren G. Harding in 1923 as an oil supply for

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216-616: The Arctic. Under the North Slope is an ancient seabed, which now contains large amounts of petroleum . Within the North Slope, there is a geological feature called the Barrow Arch — a belt of the kind of rock known to be able to serve as a trap for oil. It runs from the city of Utqiaġvik to a point just west of the Arctic National Wildlife Refuge. Ira Harkey quotes Noel Wien as stating that in

234-553: The North Slope, only a surface "active layer" of the tundra thaws each season; most of the soil is permanently frozen year-round. On top of this permafrost , water flows out to sea via shallow, braided streams or settles into pools and ponds. Along the bottom of the Landsat 7 image on the right, the rugged terrain of the Brooks Range mountains is snow-covered in places (blue areas) and exposed (pink areas) in others. Much of

252-728: The US Navy, though the presence of oil in the region had been known by American whalers for some time. It contains the bulk of Alaska's known petroleum until the Prudhoe Bay Oil Field was discovered (outside the NPRA) in 1968, followed by the Kuparuk River oil field in 1969. The petroleum extracted from the region is transferred south by means of the Trans-Alaska Pipeline System to Valdez on

270-538: The eastern Ghats and the western coastal plain is located between the Arabian Sea and the western Ghats. This article related to topography is a stub . You can help Misplaced Pages by expanding it . Fall line A fall line (or fall zone ) is the area where an upland region and a coastal plain meet and is noticeable especially where rivers cross it, with resulting rapids or waterfalls . The uplands are relatively hard crystalline basement rock , and

288-418: The fall line a good location for water mills , grist mills , and sawmills . Seeking a head of navigation with a ready supply of water power, people have long made settlements where rivers cross a fall line. The slope of rivers crossing fall zones affected settlement patterns. For example, the fall line represents the inland limit of navigation of many rivers. As such, many cities along a fall line grew as

306-538: The fall line cities. In the USA, Mid-Atlantic and Southern fall line cities include: The Laurentian Upland forms a long scarp line where it meets the Great Lakes–St. Lawrence Lowlands . Along this line numerous rivers have carved falls and canyons (listed east to west): The River Jacques-Cartier and River Saint-Maurice lack such noticeable feature because they cross the scarp through U-shaped valleys . The falls of

324-623: The region is located politically in North Slope Borough , and geographically in the Alaska North Slope basin . On August 12, 2018, a 6.4 magnitude earthquake hit the region, the most powerful recorded for the Alaskan North Slope. The region includes the Arctic National Wildlife Refuge . The entire coastal plain of Alaska has tremendous ecological importance with the densest concentration of birds in

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